Hermetic type compressor

ABSTRACT

A hermetic type compressor including balance weights installed on a rotor so as to compensate for rotating unbalance of a rotary shaft, thereby reducing a level of noise. The hermetic type compressor has a compressing unit, which compresses a refrigerant, a driving unit, which provides driving force to compress the refrigerant, a stator, a rotor that rotates in electromagnetic interaction with the stator, and a rotary shaft, which is press-fit into a center of the rotor so as to transmit the driving force of the driving unit to the compressing unit, and has an eccentric part on one end thereof. The rotor has balance weights so as to compensate for rotating unbalance of the rotary shaft caused by the eccentric part on upper and lower ends thereof, where each balance weight has a shape of a ring, part of which has at least a hollow space.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No.10-2007-0030159, filed on Mar. 28, 2007, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure relates to a hermetic type compressor. Moreparticularly, the present disclosure relates to a hermetic typecompressor in which balance weights, which are installed on a rotor soas to compensate for rotating unbalance of a rotary shaft, arestructurally improved.

2. Description of the Related Art

In general, a compressor applied to a refrigeration cycle for arefrigerator or an air conditioner has a hermetic case for an outwardappearance. The hermetic case is equipped therein with a driving unitproviding driving force for compressing a refrigerant, and a compressingunit receiving the driving force from the driving unit and compressingthe refrigerant.

The driving unit comprises a stator, and a rotor installed in the statorso as to rotate in electromagnetic interaction with the stator. A rotaryshaft is press-fit into the center of the rotor. Further, the rotaryshaft includes an eccentric part at one end thereof so as to beeccentric to the central axis of the rotary shaft. The compressing unitcompresses the refrigerant using eccentric motion of this eccentricpart.

Thus, during compressing the refrigerant, the rotary shaft causesvibration or noise while rotating in an unbalanced state due to theeccentric motion of the eccentric part. In order to compensate for thisrotating unbalance, the rotor includes balance weights having apredetermined mass at upper and lower ends thereof, which are disposedso as to cross each other at an angle of 180 degrees. Each balanceweight usually has the shape of a semi-ring because it is disposedaround the rotary shaft.

FIG. 1 illustrates the structure of a conventional hermetic typecompressor, in which a balance weight is coupled to the upper end of arotor. For reference, a reference number 3 indicates a rotary shaft.

In the case of this conventional hermetic type compressor, since thebalance weight 2 is disposed so as to be eccentric to the central axisof the rotary shaft 3, a leading end of the rotating balance weight 2excites vibration of a fluid such as a refrigerant inside a hermeticcase when the rotary shaft 3 of the rotor 1 rotates to compress therefrigerant. As a result, aeroacoustic noise of a specific frequency iscaused in the hermetic case, and thus overall driving noise of thehermetic type compressor is increased.

SUMMARY OF THE INVENTION

Accordingly, it is an aspect of the present disclosure to provide ahermetic type compressor, in which balance weights installed on a rotorso as to compensate for rotating unbalance of a rotary shaft arestructurally improved, thereby reducing a level of noise.

Additional aspects and/or advantages of the disclosure will be set forthin part in the description which follows and, in part, will be apparentfrom the description, or may be learned by practice of the disclosure.

The foregoing and/or other aspects of the present disclosure areachieved by providing a hermetic type compressor, which comprises acompressing unit, which compresses a refrigerant, a driving unit, whichprovides driving force to compress the refrigerant, and comprises astator and a rotor installed in the stator so as to rotate inelectromagnetic interaction with the stator, and a rotary shaft, whichis press-fit into a center of the rotor so as to transmit the drivingforce of the driving unit to the compressing unit, and comprises aneccentric part on one end thereof. The rotor comprises balance weightsso as to compensate for rotating unbalance of the rotary shaft caused bythe eccentric part on upper and lower ends thereof, each balance weighthas a shape of a ring, part of which has at least a hollow space.

According to an aspect of the present disclosure, each balance weightcomprises a solid part and a hollow part, both of which are integrallyformed with each other and have a shape of a semi-ring.

According to an aspect of the present disclosure, each balance weightcomprises a solid part and a hollow part, both of which are separatelyformed and coupled with each other and have a shape of a semi-ring.

According to an aspect of the present disclosure, the hollow part isopen to one face thereof which is in contact with the rotor.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the disclosure will becomeapparent and more readily appreciated from the following description ofthe embodiments, taken in conjunction with the accompanying drawings ofwhich:

FIG. 1 is a plan view illustrating the structure of a conventionalhermetic type compressor, in which a rotor is rotating in the state inwhich a balance weight is coupled to a rotor;

FIG. 2 is a sectional view illustrating the overall structure of ahermetic type compressor according to an exemplary embodiment of thepresent disclosure;

FIG. 3 is a perspective view illustrating the partial structure of ahermetic type compressor according to an exemplary embodiment of thepresent disclosure, in which balance weights are decoupled from a rotor;

FIG. 4 is a plan view illustrating the structure of a hermetic typecompressor according to an exemplary embodiment of the presentdisclosure, in which a rotor is rotating in the state in which balanceweights are coupled to a rotor; and

FIG. 5 is a perspective view illustrating the structure of a balanceweight according to another exemplary embodiment of the presentdisclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the embodiments of the presentdisclosure, examples of which are illustrated in the accompanyingdrawings, wherein like reference numerals refer to the like elementsthroughout. The embodiments are described below to explain the presentdisclosure by referring to the figures.

As illustrated in FIG. 2, a reciprocating type compressor of the presentdisclosure comprises a hermetic case 10, in which an upper case 10 a anda lower case 10 b are coupled to each other. The hermetic case 10comprises an inlet pipe 11 and an outlet pipe 12 on one side thereof.The inlet pipe 11 guides a refrigerant from the exterior to the interiorof the hermetic case 10, while the outlet pipe 12 guides the refrigerantcompressed in the hermetic case 10 to the exterior of the hermetic case10.

The hermetic case 10 is equipped therein with a compressing unit 20compressing the refrigerant, and a driving unit 20 providing drivingforce to compress the refrigerant. The compressing unit 20 and thedriving unit 20 are installed through a frame 40.

The driving unit 30 comprises a stator 31 fixed around a lower portionof the frame 40, and a rotor 32 installed in the stator 31 so as torotate in electromagnetic interaction with the stator 31.

Further, the compressing unit 20 comprises: a cylinder 21, which isintegrally formed with the frame 40 on one side of the upper portion ofa through-hole 41 at the center of the frame 40 so as to form acompression chamber 21 a for compressing the refrigerant; a piston 22,which reciprocates in the compression chamber 21 a and compresses therefrigerant; a cylinder head 23, which is coupled to one end of thecylinder 21 so as to airtightly close the compression chamber 21 a andis partitioned into a refrigerant discharge chamber 23 a and arefrigerant intake chamber 23 b; and a valve 24, which is interposedbetween the cylinder 21 and the cylinder head 23, and regulates a flowof the refrigerant that is either drawn from the refrigerant intakechamber 23 b into the compression chamber 21 a or discharged from thecompression chamber 21 a to the refrigerant discharge chamber 23 a.Here, the refrigerant intake chamber 23 b guides the refrigerant, whichis delivered into the hermetic case 10 through the inlet pipe 11, to thecompression chamber 21 a. The refrigerant discharge chamber 23 acooperates with the outlet pipe 12. An intake muffler 13 serves to guidethe refrigerant flowing into the hermetic case 10 through the inlet pipe11 to the refrigerant intake chamber 23 b in the state where pulsatingpressure is reduced.

The driving force of the driving unit 30 is transmitted to thecompressing unit 20 through a rotary shaft 50. The rotary shaft 50 isrotatably installed in the through-hole 41 at the center of the frame40. The rotary shaft 50 is press-fit into the center of the rotor 32 ata lower portion of the frame 40 so as to be rotated together with therotor 32, and comprises an eccentric part 51, which is eccentric to thecentral axis of the rotary shaft 50 and is eccentrically rotated aboutthe central axis of the rotary shaft 50, at an upper end thereof at anupper portion of the frame.

Further, a connecting rod 25 is connected between the eccentric part 51and the piston 22 in order to convert rotating motion of the rotaryshaft 50 into reciprocating motion of the piston 22.

According to this construction, when the rotary shaft 50 is rotatedtogether with the rotor 32 by electromagnetic interaction between thestator 31 and the rotor 32, the piston 22 connected with the eccentricpart 51 through the connecting rod 25 reciprocates in the compressionchamber 21 a. Thereby, the refrigerant guided into the hermetic case 10along the inlet pipe 11 is drawn into the compression chamber 21 a viathe refrigerant intake chamber 23 b of the cylinder head 23, and iscompressed in the compression chamber 21 a. The refrigerant compressedin the compression chamber 21 a is discharged to the outside of thehermetic case 10 via the refrigerant discharge chamber 23 a of thecylinder head 23 and the outlet pipe 12. This process is repeated.Thereby, the refrigerant is compressed by the compressor.

Meanwhile, while the refrigerant is compressed, the rotary shaft 50 isrotated in an unbalanced state due to the eccentric rotation of theeccentric part 51 and the reciprocating motion of the piston 22 thatoccurs in a direction perpendicular to the rotary shaft 50. As a result,the rotary shaft 50 causes vibration or noise.

Thus, in order to compensate for the rotating unbalance of the rotaryshaft 50, first and second balance weights 60 and 70 are installed onupper and lower ends of the rotor 32 respectively. In this embodiment,each of the first and second balance weights 60 and 70 has an annularappearance, as illustrated in detail in FIG. 3.

The first and second balance weights 60 and 70 comprise solid parts 61and 71, and hollow parts 62 and 72. The solid parts 61 and 71 and thehollow parts 62 and 72 have the shape of a semi-ring. The first balanceweight 60 is constructed in a manner such that the solid part 61 isintegrally formed with the hollow part 72 in a ring shape. This isequally true of the second balance weight 70.

Here, the solid parts 61 and 71 of the first and second balance weights60 and 70 function to compensate for the rotating unbalance of therotary shaft 50. The first and second balance weights 60 and 70 aredisposed so as to cross each other at an angle of 180 degrees wheninstalled on the upper and lower ends of the rotor 32.

Further, each of the first and second balance weights 60 and 70 havingthe annular appearances is symmetrical in all directions and does notprotrude outwardly from the outer surface thereof. As such, the fluidsuch as the refrigerant in the hermetic case 10 does not excitevibration when the rotor 32 is rotated as illustrated in FIG. 4. As aresult, the hermetic type compressor of this embodiment can inhibitaeroacoustic noise attributable to the rotation of the balance weights60 and 70 in the hermetic case 10, and thus reduce overall drivingnoise.

These balance weights 60 and 70 can be fixed to the rotor 32 usingrivets 32 a. To this end, the solid parts 61 and 71 comprise fasteningthrough-holes 61 a and 71 a for fastening the rivets 32 a.

The hollow parts 62 and 72 are adapted to form open faces 62 a and 72 aso as to allow the hollow interiors thereof to communicate with theexteriors thereof. All of the remaining faces other than the open faces62 a and 72 a are closed. These open faces 62 a and 72 a can facilitateforming the balance weights 60 and 70.

In other words, the balance weights 60 and 70 can be prepared by forginga solid metal member having the shape of a complete ring or by casting.In the case in which each of the balance weights 60 and 70 is adapted sothat one face thereof is partly open, this may make it difficult to forma hollow space when the balance weights 60 and 70 are formed. For thisreason, the open faces 62 a and 72 a of the balance weights 60 and 70are formed so as to completely open.

Further, in the case in which the open faces 62 a and 72 a are exposedoutside in the state where the balance weights 60 and 70 are installedon the rotor 32, the refrigerant in the hermetic case 10 may excitevibration on inner walls of the hollow parts 62 and 72. As such, whenthe first balance weight 60 is installed on the upper end of the rotor32, the open face 62 a of the first balance weight 60 preferably facesthe upper end of the rotor 32 so as to be in contact with the upper endof the rotor 32. Similarly, when the second balance weight 70 isinstalled on the lower end of the rotor 32, the open face 72 a of thesecond balance weight 70 preferably faces the lower end of the rotor 32so as to be in contact with the lower end of the rotor 32.

Further, in this embodiment, the solid part 61 and the hollow part 62are formed in one body, and the solid part 71 and the hollow part 72 arealso formed in one body. However, in another embodiment of the presentdisclosure, as illustrated in FIG. 5, the solid parts 61′ and 71′ arefabricated apart from the hollow parts 62′ and 72′, and then are coupledto the hollow parts 62′ and 72′.

In the other embodiment, the solid parts 61′ and 71′ are coupled to thehollow parts 62′ and 72′ by bolts 100. Alternatively, the solid parts61′ and 71′ may be coupled to the hollow parts 62′ and 72′ by anadhesive. The hollow parts 62′ and 72′ are also adapted to form openfaces 62 a and 72 a in the directions in which they are in contact withthe rotor 32.

As described in detail above, according to the present disclosure, thehermetic type compressor is adapted so that the balance weightsinstalled on the rotor comprise the solid parts and the hollow parts,and form the annular appearances on the whole.

Thus, the hermetic type compressor compensates for the rotatingunbalance of the rotary shaft by means of the solid parts, and preventsthe balance weights from exciting the vibration of the fluid in thehermetic case when the rotor is rotated, so that the aeroacoustic noisecan be inhibited from occurring in the hermetic case, and thus theoverall driving noise can be effectively reduced.

Although few embodiments of the present disclosure have been shown anddescribed, it would be appreciated by those skilled in the art thatchanges may be made in these embodiments without departing from theprinciples and spirit of the disclosure, the scope of which is definedin the claims and their equivalents.

1. A hermetic type compressor comprising: a compressing unit, whichcompresses a refrigerant; a driving unit, which provides driving forceto compress the refrigerant, and comprises a stator and a rotorinstalled in the stator so as to rotate in electromagnetic interactionwith the stator; and a rotary shaft, which is press-fit into a center ofthe rotor so as to transmit the driving force of the driving unit to thecompressing unit, and comprises an eccentric part on one end thereof,wherein the rotor comprises balance weights so as to compensate forrotating unbalance of the rotary shaft caused by the eccentric part onupper and lower ends thereof, each balance weight has a shape of a ring,part of which has at least a hollow space.
 2. The hermetic typecompressor as claimed in claim 1, wherein each balance weight comprisesa solid part and a hollow part, both of which are integrally formed witheach other and have a shape of a semi-ring.
 3. The hermetic typecompressor as claimed in claim 1, wherein each balance weight comprisesa solid part and a hollow part, both of which are separately formed andcoupled with each other and have a shape of a semi-ring.
 4. The hermetictype compressor as claimed in claim 2 or 3, wherein the hollow part isopen to one face thereof which is in contact with the rotor.